True story: Giant sloth was found under Sea-Tac Airport

Is it true that a giant ground sloth was found at Sea-Tac International Airport?

Courtesy of the Burke Museum

Yes! Fifty years ago remains of a giant ground sloth, termed Megalonyx, were unearthed as construction crews were installing a lighting system along a runway at Sea-Tac airport. Nearly two-thirds of the sloths bones were perfectly preserved, with only the skull and some of the neck and limb bones missing. Casts were taken from another Megalonyx specimen and were used to complete the skeleton that you can see on display at the Burke Museum.

Megalonyx and other types of giant sloths roamed North America during the Pleistocene epoch (2.5 million to 12,000 years ago) eating plant materials, roots, and tubers and fending off attacks from saber-toothed cats.

For history buffs, the first Megalonyx fossil discovered in the United States was by the third president of the United States, Thomas Jefferson. He found it in 1796 in a saltpeter mine in what is now West Virginia.

Want to learn more about the Sea-Tac Sloth? Watch this video created by Mary Jean, Kelsie and Rachel, students in the University of Washington’s COM460 class.